Suspension bridge



OCt 21,' 1947. H, SHOEMAKER 2,429,332

SUSPENS ION BRIDGE.'

Filed Oct. 14, 1944 2 Sheets-Sheet l Uct. 21,A 1947. 1.. H. SHOENVIIAKER 2,429,332

lSUSPENSION BRIDGE I Filed Ooi. 14, 1944 2 Sheets-Sheet- 2 fv VEN Toe. y By Qu/.s H. Hamm/Efe Q12 7 Hann/.5, MEC/, .57E/2' CHA/ans Foe ne HHM ATTOENEYS Patented Oct. 21, 1947 fj UNITED STATESI PATENT oFFlcE SUSPENSION BRIDGE Louis H. Shoemaker; Santa Monica, Calif. Application October 14, 1944, Serial No. 558,653

l My invention relates to suspension bridges having cables formed of wire. Such bridges are generally,A but not always, used to span a river or other body of water, and my invention will be described for convenience as if it were so used.

lIn the present type of bridge and in a bridge embodying my invention, a massive abutment, generally designated as an anchorage, is provided at each end of the bridge, which abutment carries what may be termed an attachment structure, to which one end of each of the cables is secured, the attachment being solidly anchored in place on the anchorage.

The usual method of building such` a bridge is to rst erect a small temporary suspension bridge, and to string the individual Wires of the cable from `attachment structure to attachment structure, to which the ends of the wires are attached by temporary fastenings and suspended on temporary supports at the towers, the floor of the temporary bridge being used as a Working platform, 4where the Wires are hunched and bound together to form a round cable, which is then covered with suitable lashings and a protective covering. Suspension bridge cables are now commonly made upon the floor of such a temporary bridge. 'Y It is an object of my invention to construct a cable for a suspension bridge without the use of a temporary bridge, each wire of the cable being strung from attachment structure to attachment structure, and each end of each wire being secured to the attachment structure in approximately its nal position Without the support of such a temporary bridge.

In bridges as now constructed, in which the cable is assembled in approximately circular section from the oor of a temporary bridge, it is extremely diii'icult to equally stress all the Wires of the cable, and a relatively high factor of safety must be applied. It is an object of my invention to provide a structure having an equally high factor of safety, but to reduce the cost by a denite and logical arrangement of the individual Wires so that they will be more nearly equally stressed than is now possible, and by eliminating the large bending stresses now induced in the Wires by bending around the strand shoes used as attachments at the anchorages.

It is further an object of my invention to pro- 4 Claims. (Cl. 14-21) duce a cable of approximately rectangular, and I usually square section. The individual Wires, as they leave the attachment members, are evenly disposed over a rectangular section, and they can thenbe assembled in contact with each other 2 in a rectangular cable, if they are initially of the proper length, so that they are each subjected to the same stress in the completed cable.

Further objects and advantages will be made evident hereinafter.

Referring to the drawings, which are for illustrative purposes only and which disclose my preferred method of constructing and erecting a suspension bridge:

Fig. 1 is a side elevation of a suspension bridge;

Fig. 2 is a side elevation of a cable attachment structure;

Fig. 3 is a plan view of the attachment structure, certain parts being omitted to facilitate better understanding thereof;

Fig. 4 is an elevation of the structure shown in Fig. 3;

Fig. 5 is a plan View of two attachment, plates;

Fig. 6 is an end View of the attachment plates shown in Fig. 5;

Fig. 7 is a side elevation of a wire end or head;

Fig. 8 is a cross section takenon the line 8 8 of Fig. 7;

Fig. 9 is a side elevation of an alternative form of wire end or head;

Fig. 10 is an end elevation of the wire end or head shown in Fig. 9;

Fig. 11 is a diagram shown in perspective illustrating the curvature of the side and attachment plates.

In Fig. 1 I showa suspension bridge as seen when looking north over a `river l having an east bank 2 and a west bank 3; It is, of course, understood that the bridge need not necessarily be over a river, and the points of the compass used herein were adopted purely for descriptive purposes. T'he cable 4 of the bridge is attached at its east end to an attachment structure 5 and at its West end to an attachment structure 6. A plurality of cables 4 are, of course, used in an actual bridge.

The attachment structures 5 and areeach mounted on an anchorage Il, the east anchoragebeing shown in Fig. 2, this anchorage being usually a block of concrete heavy enough to take the pull of the cables 4. The attachment structures 5 and 6 are duplicates of each other, the east attachment structure being shown in Figs. 3 and 4. This structure 5 is anchored by eye bars l 2 and I3 to members embedded in the anchorage Il. The cables 4 are secured in the attachment structures 5 and 6 in a novel manner which will hereinafter be explained. The cables 4 pass over an east tower `25 and a West tower 26.

It is, of course, understood that suspension Ii the, attachment. structuresand attachmentn members: are properly designed and the wirres off each layer all have the same effective length, the

wires will fall into their natural places in the.

cable and form a compact cable in which the wires are equally stressed. This length islcarefully calculated, and the Wires are cut to the proper length preferably before being' taken' to' the bridge site. Heads are formed or secured onf,

both ends of each individual Wire I5. These heads may be or" Various forms, those shown in- Figs. '7 to 10, inclusivabeing quite convenient. Irl-.both the: forma shown in Fi'gsa. '7J and: 8: andi that shown. Figs.. 9 an'dl.0, a;A doable coned inner split sleeve t6? isiused, this sleevebeing three parts. As shownv inxg; 7. eazch" of the: sleeves is of a definite diameter in the. center andtafp'ers toward; the: ends.. A primary? collar I IE and' a seconda-ry collar I 82' eachgh'ave a. comcali opening fittin-g: over the sleeve'. 'l'.hesleeve'-A IZE- hasla. cylindrical opening therethrough to kreceive the' wire I'; Ehe uiver'end I9xof eachzprimaryicollar l-" abuts against arr. attachment; means, as Willi later explained. The direct pull of the wires I.,.w.lii'cl1'v arer slightly' corrugated Where.4 they` pass through the sleeve,- is transmitted'. to'. the. sleeve', the'. three parts of which are pressedtvth consi'de'rable'l pres'- suce against' the Wire'. The, pull. is' transmitted from the sleeves to the primary collars I'I. The nut or projection; Zzli on 22. at the' end' of. each wireis: merely-for the' purpose of preventing: the secondary collar I3 from Working loose.; Aiathe stress is put. on: the wire, this.: stress isi taken` by an. attachment plat'ei'which thrusts against.. the river end I9 of each collar Il, the collarsA l'l and I-8i being forced tcnvardY each other,Y thus ccmpressing the split sleeve I6 againstlthe Wiref I5 and gripping it firmly.. The headsA showin are. azvpreferred form, and, obviously; .-mechariically.' equinalent headsmight beiormedibyotlien rne'anssV All that. is neededisf to' province an. enlarged head.. on each end of each wire I5 to take the pull of.' that Wire. These headsA are generally' designated.' by the numeral 21; Y

In practice,` the' finished' cableliis madeiup' of several strands 32- for convenience' in* assembly; For example, the cable- 4' may be madev up o'f three' strands' andy may contain 75.` layers 'of '75 Wires each. EachStrand'k 3'2f Will consist of. 75 layers of 25Wires each. Ther ends. oi the wires are heldinattachment: plates 29 and 35i; two of plates 1, as shown in Figs. 3 and 4, the pull of the cables 4 being transmitted through the side plates I to the eye bars I2 and I3 and thus back to the anchorage II as shown in Fig. 2.

Referring to Fig. 2, the strands 32 pass to and through saddle castings 40, where they are brought together to form the cable 4. As illustrated in Fig. 11, the back edge 8 of each of said side plates, I isY curved man, arc struck from an axis` A, which is locatedfnearrthe saddle: plates 40, on the line of the intersection of the planes S of the top and bottom surfaces of the attachment plates.

Similarly, the back edges I!! of the attachment plates curve in an arc struck from the axis A which is located near the saddle plates 40' on the line formed by the intersection of the.

planes S' of. the side plates. Accordingly, the lengthV of all wires between the center of the saddie' plates 4l] and the backs of the attachment plates is the same. It will be noted that the wires I5Y divergeL both horizontally andl vertically between theV saddle plates and 4the' attachment plates. The completed bridge will usually have a plurality' of cablesoneach side of' ther bridge; The-backs of the attachment plates of all three strands 32 ofa cable are eachzinan annular suriace centering in a point on an axis A as above described?.

Referring to Fig. 2, the Wires I5, after leaving the attachment' plates, pass through the saddle castings 4b, where the wires' I5' are consolidated to' form a.' cable 4. Passing West of the saddle castings 40, the wires I5" are bunchedtogether ina. rectangular. cable 4. Passing eastwardly from the. saddle castings40', as'shovvn in Figs; 2, 3, and 4-the1wires of' eachI strand 32 andthe strans themseives'- fan` out to` give sufficient' space for the heads'.

The' principali advantage of my invention is that: it makes a better and:y safer bridge. Each wire I5. carries its own safe' load and occupies without'. interference its planned position in the final structure'. The loads imposed are applied which areshown in Figs; 5 and'; Each-.ofi these plates has a front edge 9 and a baclczedge [wand is provided on the top andibottomjthereof'with grooves. which formiA holes 31. slightlyl larger' than the Wires I5, butismallerindiamet'er'than the heads 21; containing '75: layers o'f 75 Wires each', there are 2.5,- holes= 3I- between each' pair. of plates and'. 76 plates 29- andi ior'each strand andatcea'chend of' each' strand; These. plates' are: solidly clamped together in the' finished. bridge; anditliey.l transfer the' pull ofthe completed' cables-'41, e'a'ch containing 5625 or more or'lcss Wires- I5; The attachment plates aresecuredin-the attachment structures 5, the frontedge' of4 ea'chf of said attachment plates-abutting onthe back-edges 8f of side In the actual constructionloff al cable uniformly tothe'top ofithecable 4-v and, due' to' the parallel positionv of the Wires` inthe cable', are uniformly distributed among all the Wires.V

I claim as my invention:

l'. An. attachment'. me'ansfor taking the pulli of as cable of a' suspension'` bridge, said cable consistingoseparate Wires', each-Wire having a head secuned: tothe endlo saidwire, theheadbeing oflarger;diam'eter than the Wire, each of sai'dfhea'ds beingi distinct` and'. separate' from each of the other heads; comprising;v attachment plates; each of which has a plurality'o'fgrooves, each groove' being offsuch sizethatv awrecan lie' therein but a-.headcannot passztherethrough so that the' pull of eachvvire' is'Y transmitted by'the'head' of said Wire.Y to` the back: of said' attachment plate; two side plates,. one: ofthe ends` oi the front edges oeach of said attachment plates abuttingagainst the-back edge'of one'df thefsaid side plates, the other endi ofeachof said;attachmentlplates'abuttingaigainst; the back edge off' the' otl'rer of said sideplates', the pull' of the cable'. against each ol said i' attachment plates.I being transmitted to f said side: plates; andmeans by which' thevv pull of. the cableV on= said.v side platesf is; transmittedlto' mem'- bers secured to fixed anchorageof: saidlbridge 2f. Anattachment meansffor takingV the pul'lof a' cabletY of a susp'ensionbridge', said! cable consisting; of. separate wires, each having' ahead secured.' to` theend of saidW-iie, the head being'of larger diameter thanitlie'wire; each of'said heads being distinct and separatef'rom eachof'the other heads, comprising: attachment plates, each of which has a plurality of grooves, each groove being of such size that a wire can lie therein but a head cannot pass therethrough so that the pull of each wire is transmitted by the head of said Wire to the back of said attachment plate; two

.side plates, one of the ends of the front edges of each of said attachment plates abutting against the back edge of one of the said side plates, the other end of each of said attachment plates abutting against the back edge of the other of said side plates, the pull of the cable against each of said attachment plates being transmitted to said side plates; and means by which the pull of the cable on said side plates is transmitted to members secured to xed anchorage of said bridge, the back edge of each of said side plates being curved in an arc struck from an axis located on the line formed by the intersection of the planes of the top and bottom surfaces of the attachment plates.

3. An attachment means for taking the pull of a cable of a suspension bridge, said cable consisting of separate wires, each having a head secured to the end of said wire, said head being of larger diameter than the wire, each of said heads being distinct and separate from each of the other heads, comprising: attachment plates, each of which has a plurality of grooves, each groove being of such size that a wire can lie therein but a head cannot pass therethrough so that the pull of each wire is transmitted by the head of said wire to the back of said attachment plate; two side plates, one of the ends of the front edges of each of said attachment plates abutting against the back edge of one of the said side plates, the other end of each of said attachment plates abutting against the back edge of the other of said side plates, the pull of the cable against each of said attachment plates being transmitted to said side plates; and means by which the pull of the cable on said side plates is transmitted to` members secured to xed anchorage of said bridge, the back edge of each of said attachment plates being curved in an arc struck from an axis located on the line formed by the intersection of the planes of said side plates.

4f; An attachment means for taking the pull of a cable of a suspension bridge, said cable consisting of separate wires, each having a head secured to the end of said wire, said head being of 6 larger diameter than the wire, each of said heads being distinct and separate from each of the other heads, comprising; attachment plates, each of which has a plurality of grooves, each groove being of such size that a wire can lie therein but a head cannot pass therethrough so that the pull of each wire is transmitted by the head of said wire to the back of said attachment plate; two side plates, on of the ends of the front edges of each of said attachment plates abutting against the back edge of one of the said side plates, the other end of each of said attachment plates abutting against the back edge of the other of said side plates, the pull of the cable against each of said attachment plates being transmitted to said side plates; and means by which the pull of the cable on said side plates is transmitted to members secured to xed anchorage of said bridge, the back edge of each of said side plates being curved in an arc struck from an axis located on the line formed by the intersection of the planes of the top and bottom surfaces of said attachment plates, the back edge of each of said attachment plates being curved in an arc struck from an axis located on the line formed by the intersection of the planes of said side plates.

LOUIS H. SHOEMAKER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name f Date 378,697 Lindenthal Feb. 28, 1888 411,499 Greer Sept. 24, 1889 1,453,084 Strauss Apr. 24, 1923 1,537,698 Robinson May 12, 1925 1,852,683 Sunderland Apr. 5, 1932 1,899,998 Sunderland Mar. 7, 1933 2,021,575 Lloyd Nov. 19, 1935 2,040,572 Shearwood May 12, 1936 2,127,235 Robinson Aug. 16, 1938 2,132,269 McHugh Oct. 4, 1938 2,141,138 Howe et al Dec. 20, 1938 2,178,147 Moisseiff et al Oct. 31, 1939 FOREIGN PATENTS Number Country Date 112,156 Australia 1940 Certicate of Correction Patent No. 2,429,332. October 21, 1947.

' LOUIS H. SHOEMAKER A It is hereby certed that errors appear in the printed speecetion of the above numbered patent requirin correction es follows: Column 3, line 16, for preferably read probably; line 38, str' e out or 22; line 74, after edge insert the numeral 9; column 4, line 36, for straus readstrcmds; column 6, line 9, for on of read. one of; and that the said Letters Patent should be read with these corrections therein that the seme may conform to the record of the case in the Patent Oflice.

Signed and sealed this 20th day of January, A. D. 1948.

THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

